C: fix behaviour of nested try/catch statements

core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java

@@ -151,6 +151,8 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
     private ObjectIntMap<IdentifiedStatement> labelMap = new ObjectIntHashMap<>();
     private Set<IdentifiedStatement> usedAsBreakTarget = new HashSet<>();
     private Set<IdentifiedStatement> usedAsContinueTarget = new HashSet<>();
+    private Map<IdentifiedStatement, Integer> tryDepthByStatements = new HashMap<>();
+    private int tryDepth;
 
     static {
         BUFFER_TYPES.put(ByteBuffer.class.getName(), "int8_t");
@@ -1197,8 +1199,7 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         IdentifiedStatement oldDefaultBreakTarget = defaultBreakTarget;
         defaultBreakTarget = statement;
 
-        int statementId = labelMap.size() + 1;
+        int statementId = registerIdentifiedStatement(statement);
-        labelMap.put(statement, statementId);
 
         pushLocation(statement.getValue().getLocation());
         writer.print("switch (");
@@ -1243,8 +1244,7 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         defaultBreakTarget = statement;
         defaultContinueTarget = statement;
 
-        int statementId = labelMap.size() + 1;
+        int statementId = registerIdentifiedStatement(statement);
-        labelMap.put(statement, statementId);
 
         writer.print("while (");
         if (statement.getCondition() != null) {
@@ -1276,8 +1276,7 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
 
     @Override
     public void visit(BlockStatement statement) {
-        int statementId = labelMap.size() + 1;
+        int statementId = registerIdentifiedStatement(statement);
-        labelMap.put(statement, statementId);
 
         visitMany(statement.getBody());
 
@@ -1293,8 +1292,7 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         if (target == null) {
             target = defaultBreakTarget;
         }
-        int id = labelMap.get(target);
+        jumpToTarget(target, "teavm_label_");
-        writer.println("goto teavm_label_" + id + ";");
         usedAsBreakTarget.add(target);
         popLocation(statement.getLocation());
     }
@@ -1306,12 +1304,28 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         if (target == null) {
             target = defaultContinueTarget;
         }
-        int id = labelMap.get(target);
+        jumpToTarget(target, "teavm_cnt_");
-        writer.println("goto teavm_cnt_" + id + ";");
         usedAsContinueTarget.add(target);
         popLocation(statement.getLocation());
     }
 
+    private int registerIdentifiedStatement(IdentifiedStatement statement) {
+        tryDepthByStatements.put(statement, tryDepth);
+        int statementId = labelMap.size() + 1;
+        labelMap.put(statement, statementId);
+        return statementId;
+    }
+
+    private void jumpToTarget(IdentifiedStatement target, String prefix) {
+        int targetDepth = tryDepthByStatements.get(target);
+        while (targetDepth < tryDepth) {
+            targetDepth++;
+            writer.println("TEAVM_RESTORE_JUMP_BUFFER;");
+        }
+        int id = labelMap.get(target);
+        writer.println("goto " + prefix + id + ";");
+    }
+
     @Override
     public void visit(ReturnStatement statement) {
         pushLocation(statement.getLocation());
@@ -1398,7 +1412,10 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         }
 
         writer.println("TEAVM_TRY").indent();
+        tryDepth++;
         visitMany(statement.getProtectedBody());
+        tryDepth--;
+        handlers.subList(firstId, handlers.size()).clear();
         writer.outdent().println("TEAVM_CATCH").indent();
 
         for (int i = tryCatchStatements.size() - 1; i >= 0; --i) {
@@ -1421,8 +1438,6 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
             writer.outdent().println("}");
         }
 
-        handlers.subList(firstId, handlers.size()).clear();
-
         writer.outdent().println("TEAVM_END_TRY");
     }
 

core/src/main/java/org/teavm/runtime/ExceptionHandling.java

@@ -108,13 +108,17 @@ public final class ExceptionHandling {
                 while (handler != null) {
                     if (handler.exceptionClass == null || handler.exceptionClass.isSupertypeOf.apply(exceptionClass)) {
                         handlerId = handler.id;
-                        ShadowStack.setExceptionHandlerId(stackFrame, handler.id);
+                        if (!isJumpSupported()) {
+                            ShadowStack.setExceptionHandlerId(stackFrame, handlerId);
+                        }
                         break stackLoop;
                     }
                     handler = handler.next;
                 }
 
-                ShadowStack.setExceptionHandlerId(stackFrame, callSiteId - 1);
+                if (!isJumpSupported()) {
+                    ShadowStack.setExceptionHandlerId(stackFrame, callSiteId - 1);
+                }
             }
             stackFrame = ShadowStack.getNextStackFrame(stackFrame);
         }

core/src/main/resources/org/teavm/backend/c/exceptions.h

@@ -10,21 +10,25 @@
 
 #if TEAVM_USE_SETJMP
     #define TEAVM_JUMP_SUPPORTED 1
+
+    #define TEAVM_RESTORE_JUMP_BUFFER \
+        teavm_shadowStack.header.jmpTarget = teavm_shadowStack.header.jmpTarget->previous
+
     #define TEAVM_TRY \
         do { \
-            jmp_buf teavm_tryBuffer; \
+            TeaVM_LongjmpDesc teavm_longJmpdesc; \
-            jmp_buf* teavm_oldTryBuffer = teavm_shadowStack.header.jmpTarget; \
+            teavm_longJmpdesc.previous = teavm_shadowStack.header.jmpTarget; \
-            teavm_shadowStack.header.jmpTarget = &teavm_tryBuffer; \
+            teavm_shadowStack.header.jmpTarget = &teavm_longJmpdesc; \
-            int teavm_exceptionHandler = setjmp(teavm_tryBuffer); \
+            int teavm_exceptionHandler = setjmp(teavm_longJmpdesc.buffer); \
             if (teavm_exceptionHandler == 0) {
     #define TEAVM_CATCH \
-                teavm_shadowStack.header.jmpTarget = teavm_oldTryBuffer; \
+                TEAVM_RESTORE_JUMP_BUFFER; \
             } else { \
-                teavm_shadowStack.header.jmpTarget = teavm_oldTryBuffer; \
+                TEAVM_RESTORE_JUMP_BUFFER; \
                 switch (teavm_exceptionHandler) {
     #define TEAVM_END_TRY \
                     default: \
-                        longjmp(*teavm_oldTryBuffer, teavm_exceptionHandler); \
+                        longjmp(teavm_shadowStack.header.jmpTarget->buffer, teavm_exceptionHandler); \
                         break; \
                 } \
             } \
@@ -32,7 +36,7 @@
 
     #define TEAVM_JUMP_TO_FRAME(frame, id) \
         teavm_stackTop = (TeaVM_StackFrame*) (frame); \
-        longjmp(*teavm_stackTop->jmpTarget, id)
+        longjmp(teavm_stackTop->jmpTarget->buffer, id)
 
 
     #if TEAVM_UNIX

core/src/main/resources/org/teavm/backend/c/stack.h

@@ -35,13 +35,20 @@ typedef struct TeaVM_CallSite {
     TeaVM_CallSiteLocation* location;
 } TeaVM_CallSite;
 
+#if TEAVM_USE_SETJMP
+    typedef struct TeaVM_LongjmpDesc {
+        jmp_buf buffer;
+        struct TeaVM_LongjmpDesc* previous;
+    } TeaVM_LongjmpDesc;
+#endif
+
 typedef struct TeaVM_StackFrame {
     struct TeaVM_StackFrame* next;
     #if TEAVM_INCREMENTAL
         TeaVM_CallSite* callSites;
     #endif
     #if TEAVM_USE_SETJMP
-        jmp_buf* jmpTarget;
+        TeaVM_LongjmpDesc* jmpTarget;
     #endif
     int32_t size;
     int32_t callSiteId;